The present invention is related to Japanese patent application No. Hei. 11-318652, filed Nov. 9, 1999 and application No. Hei. 2000-255906, filed Aug. 25, 2000; the contents of which are incorporated herein by reference.
The present invention relates to a seated person determination apparatus for vehicle seats, and more particularly, to a determination apparatus for vehicle seats that distinguishes between adults, children and objects.
In a conventional apparatus for determining the seated condition of seated persons, an apparatus utilized in vehicle air bag systems, determination of the type of person seated is made by imbedding pressure sensors in the seat pad of the seat. These sensors are arranged so that the body weight of the person seated is detected as a load by the pressure sensors.
In a seated condition determination apparatus mentioned above, the determination standard is either the detected load or the area determined by the distribution of the detected load. In other words, there is no information concerning the shape contained in either the detected load or its area of distribution. Consequently, the determination standard fluctuates, caused by the person seated shifting his or her position, or by the vertical movements of the vehicle traveling on rough roads.
For instance, where the actual body weight of the person seated and the load applied to the seat was reversed. The load detected by the pressure sensor fluctuated as the person seated changed the sitting attitude. Consequently, problems occur in the determination method using a detected load, including misjudging adult for a child, or misjudging a child for an adult.
In addition, when a child seat is attached to the seat, sometimes, a greater load is exerted onto to the seat than that exerted by a seated adult. Consequently, when determination is made based on this detected load, a child seat may be misjudged for an adult.
The present invention provides a seated person determination apparatus for vehicle seats that accurately differentiates the type of person seated, or differentiates a person seated from an object such as a child seat. This is accomplished by utilizing the shape of the standard surface distribution of the load that simulates the shape of contact surface formed between the human buttocks and the surface of seat pad. Specifically, the present invention provides a seat sensor composed of a plurality of sensor portions placed in a seat pad of a vehicle seat distributed in a plane parallel with the surface of the seat. The load-exerted on the surface of the seat by a person seated or an object placed on the seat is detected by the plurality of sensor portions of the seat sensor located in corresponding position.
The present invention also calculates a degree of conformity between the shape of the surface distribution of the load detected by the plurality of sensor portions and the shape of the standard surface distribution of the load. The shape of the standard surface distribution of the load, mentioned above, simulates the shape of contact surface formed between the buttocks of the person seated and the surface of seat. This determination is made utilizing the fact that the shape of contact surface, formed between the buttocks of the person seated and the surface of seat pad, remains nearly constant regardless of the shift in the sitting attitude of the person seated. A shape of a standard surface distribution of the load simulating the shape of the contact surface formed between the seated person""s buttocks and the surface of seat pad has been adopted. The type of person seated is differentiated from an object placed on the seat, according to the degree of conformity between the shape of the surface distribution of the load detected by each sensor, and the shape of the standard surface distribution of the load. This is accomplished without relying on the weight of the person seated or the area of the load distribution. Consequently, the accuracy of determination, differentiating the type of person seated from an object placed on the seat is significantly improved.
In another aspect, the means of calculating the degree of conformity makes the calculation from the shape of the standard surface distribution of the load, mentioned above, and the shape of the surface distribution of detected load, mentioned above. The degree of conformity is calculated as a child""s pattern correlation coefficient and adult""s pattern correlation coefficient, utilizing a cross correlation method.
The decision means determines whether the child""s pattern correlation coefficient and the adult""s pattern correlation coefficient match the human area or the object placed on the seat area. The human area and the object placed on the seat area are established by matching the distribution of the correlation coefficients with a large number of cases of human and objects placed on the seat. The child""s pattern correlation coefficient and adult""s pattern correlation coefficient, obtained from the cross correlation method, are utilized to determine whether it matches the human area or object placed on the seat area. The type of person seated is determined in this manner by differentiating it from the object placed on the seat. In another aspect, the means of calculating the degree of conformity makes the calculation from the shape of the standard surface distribution of the load, mentioned above, and the shape of the surface distribution of the detected load, mentioned above. The degree of conformity is calculated as a child""s pattern correlation coefficient and adult""s pattern correlation coefficient, utilizing the cross correlation method.
The decision means differentiates the type of person seated from an object placed on the seat by determining which of the adult""s area, child""s area or object placed on the seat area matches the child""s pattern correlation coefficient and adult""s pattern correlation coefficient. The child""s area, adult""s area and the object placed on the seat area are established by, matching the distribution of these correlation coefficients with large number of cases of adults, children, and objects placed on the seats. The determination made, by differentiating the type of person seated from an object placed on the seat in this manner are the characteristics of this apparatus.
The type of person seated is determined by differentiating it from the object placed on the seat in this manner. The child""s pattern correlation coefficient and adult""s pattern correlation coefficient obtained from the cross correlation method are utilized to determine whether it matches the adult""s area, child""s area, or the objects placed on the seat area. In another aspect, the present invention comprises a seat sensor composed of the plurality of sensor portions placed in the seat pad of vehicle seats, distributed in a plane parallel to the surface of the seat pad. The load exerted on the surface of the seat pad by a person seated is detected by the plurality of sensor portions of the seat sensor located in corresponding positions. A means is provided to calculate a degree of conformity between the shape of the surface distribution of the load detected by the plurality of sensor portions, mentioned above, and the shape of the standard surface distribution of the load. The shape of the standard surface distribution of the load simulates the shape of the contact surface formed by the buttocks of the person seated and the surface of seat. A decision means is provided to differentiate the type of person seated on the seat according to the degree of conformity.
The type of person seated is determined according to the degree of conformity between the shape of the surface distribution of the load detected by each sensor portion of the seat sensors and the shape of the standard surface distribution of the load. The determination is made without having to depend on the weight of the person seated or the area of the load distribution. Therefore, the accuracy of determining the type of person seated is increased significantly.
In another aspect, the means of calculating the degree of conformity makes the calculation from the shape of the standard surface distribution of the load, mentioned above, and the shape of the surface distribution of the detected load, mentioned above. The degree of conformity is calculated as the child""s pattern correlation coefficient and adult""s pattern correlation coefficient, utilizing the cross correlation method.
The decision means determines whether the child""s pattern correlation coefficient and the adult""s pattern correlation coefficient match the adult""s area or child""s area. The adult""s area and the child""s area are established by matching the distribution of these correlation coefficients with large number of cases of adults, and children seated on the seat. Differentiating the type of person seated in this manner is the characteristic of this apparatus. The type of person seated is determined by deciding whether it matches the adult""s area or child""s area utilizing the children""s pattern correlation coefficient and adult""s pattern correlation coefficient.
In another aspect, the seated person determination apparatus for vehicle seats comprises a seat sensor composed of the plurality of sensor portions placed in the seat pad of vehicle seats. The sensor portions are distributed in matrix form, in parallel to the surface of the seat. The load exerted on the surface of the seat, mentioned above, by a person seated is detected by the plurality of sensor portions of the seat sensor located in corresponding positions
In another aspect of the invention, a means is provided to calculate the sum of each load detected, out of the load detected by the plurality of sensor portions, that show movement of the seated person, from opposite sides of the seat pad surface in left and right direction, toward the center of the seat pad surface in left and right direction, on a surface parallel to a plane orthogonal to the surface of seat pad in left and right direction. The sum is calculated in a range below the prescribed load.
In another aspect of the invention, a seated person determination apparatus for vehicle seats, comprises a seat sensor composed of the plurality of sensor portions placed in the seat pad of vehicle seats. The sensor portions are distributed in a plane parallel to the surface of the seat. The load exerted on the surface of the seat, mentioned above, by a person seated or by an object placed on the seat is detected by the plurality of sensor portions of the seat sensor located in corresponding positions. A conformity calculating device calculating a degree of conformity between the shape of the surface distribution of the load detected by the plurality of sensor portions mentioned above, and the shape of the standard surface distribution of the load. The shape of the standard surface distribution of the load simulates the shape of contact surface formed by the buttocks of the person seated and the surface of seat. A means to calculate the sum of each detected load, that shows movement of the seated person from opposite sides of the seat pad surface toward its center in left and right direction, out of the detected load of the plurality of sensor portions. The calculation is made in a range below the prescribed load. A means is provided to synthesize the synthesized data that enable determination of whether the person seated is an adult or a child, from the sum of the load calculated by the means of calculating the sum and the degree of conformity. It also comprises a decision means to determine whether the person seated is an adult or a child, differentiating it from an object placed on the seat based on the synthesized data.
By synthesizing the data from the degree of conformity and the sum of the load calculated by the means of calculating the sum, that enables differentiation of a child seated from an adult seated.
A means is provided to calculate the sum of each load detected, out of the load detected by the plurality of sensor portions that show movement of the seated person, from opposite sides of the seat pad surface in left and right direction, toward the center of the seat pad surface in left and right direction, on a surface parallel to a plane orthogonal to the surface of seat pad in left and right direction. The sum of the load is calculated in a range less than the prescribed load.
In another aspect, a seated person determination apparatus for vehicle seats, comprises a seat sensor composed of the plurality of sensor portions placed in the seat pad of vehicle seats. The sensor portions are distributed in a plane parallel to the surface of the seat. The load exerted on the surface of the seat, mentioned above, by a person seated or an object placed on the seat is detected by the plurality of sensor portions, of the seat sensor, located in corresponding positions.
A means is provided to calculate a degree of conformity between the shape of the surface distribution of the load detected by the plurality of sensor portions and the shape of the standard surface distribution of the load. The shape of the standard surface distribution of the load simulates the shape of contact surface formed by the buttocks of the person seated and the surface of seat.
A means is provided to calculate the sum of each load detected, out of the load detected by the plurality of sensor portions, that show movement of the seated person, from opposite sides of the seat pad surface toward the center of the seat pad surface in left and right direction. The sum is calculated in a range below the prescribed load.
A means is provided to synthesize the synthesized data that enable determination of whether the person seated is an adult or a child, from the sum of the load calculated by the means of calculating the sum, and the degree of conformity. A decision means is provided to determine whether the person seated is an adult or a child, based on the synthesized data, mentioned above.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.